Double pipe heat exchanger having multi-directional connector and air conditioner for vehicle including the same

ABSTRACT

The present invention relates to a dual pipe heat exchanger and an air conditioner for a vehicle including the same. The present invention relates to a dual pipe heat exchanger having a multi-directional connector construction in which a connector forming the dual pipe heat exchanger includes a first block and a second block and positions where a first fluid supply pipe and internal and external pipes are combined and where a second fluid supply pipe is combined can be freely set, and an air conditioner for a vehicle including the same.

PRIORITY

This application claims the benefit under 35 U.S.C. §119(a) of a Korean patent application filed on Dec. 12, 2011 in the Korean Intellectual Property Office and assigned Serial No. 10-2011-0132543, the entire disclosure of which is hereby incorporated by reference.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No. 10-2011-0132543, filed Dec. 12, 2011, which is hereby incorporated by reference in its entirety into this application.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to a dual pipe heat exchanger and an air conditioner for a vehicle including the same and, more particularly, to a dual pipe heat exchanger, which enables a heat exchanger including a dual pipe to be easily assembled in a narrow space because a coupling relation between a pipe for supplying a fluid to a space between an internal pipe and an external pipe and a dual pipe connector can be freely formed and an air conditioner for a vehicle including the dual pipe heat exchanger.

2. Description of the Related Art

Various forms of heat exchangers are being used in an air conditioner for a vehicle. From among them, a heat exchanger having a dual pipe form is being widely used. The dual pipe type heat exchanger, as shown in Patent Document 1, includes an internal pipe configured to form a low pressure passage through which a low temperature/low pressure coolant flows, an external pipe combined with the outer circumferential face of the internal pipe in a dual pipe form and configured to form a high pressure passage through which a high temperature/high pressure coolant flows, and a high temperature/high pressure fluid inlet/outlet pipe configured to receive and discharge the high temperature/high pressure coolant through a space between the internal pipe and the external pipe.

In this dual pipe heat exchanger, a heat exchange is performed between the low temperature/low pressure coolant flowing through the internal pipe and the high temperature/high pressure coolant flowing through the space between the internal pipe and the external pipe.

Meanwhile, in the conventional dual pipe heat exchanger, a connector is used to couple the high temperature/high pressure fluid inlet/outlet pipe and the external pipe. As disclosed in Patent Document 1, a connector is formed so that a high temperature/high pressure fluid inlet/outlet pipe is vertically combined with an external pipe.

Meanwhile, in the case of a dual pipe heat exchanger used in an air conditioner for a vehicle, it is necessary to minimize an installation space due to a spatial limit to an installation place and to widely secure the degree of freedom in the design in coupling the pipe and other elements forming the air conditioner, such as a compressor or an evaporator.

The conventional dual pipe heat exchanger is problematic in that the place where the dual pipe heat exchanger or the high temperature/high pressure fluid inlet/outlet pipe will be installed is greatly limited because the high temperature/high pressure fluid inlet/outlet pipe combined with the external pipe is combined with the external pipe only in the vertical direction.

For this reason, the conventional dual pipe heat exchanger is problematic in that a variety of design changes cannot be applied thereto when the dual pipe heat exchanger is installed in a vehicle and the installation space cannot be easily minimized.

PRIOR ART DOCUMENT Patent Document

-   Patent Document 1 Korean Patent Laid-Open Publication No     2009-0029891

SUMMARY OF THE INVENTION

Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a dual pipe heat exchanger, which enables a high temperature/high pressure fluid inlet/outlet pipe to be combined with an external pipe that, forming the dual pipe heat exchanger, at various angles and in various directions.

In order to achieve the above object, a dual pipe heat exchanger in accordance with an embodiment of the present invention include an external pipe configured to have a plurality of protrusions formed therein, the protrusions being protruded in the central direction of the external pipe from an inner circumferential face thereof and extended in a straight-line form in the length direction of the external pipe; an internal pipe inserted into the external pipe; a first fluid supply pipe combined with one end of the internal pipe; and a connector configured to include a space in which the external pipe, the internal pipe, and the first fluid supply pipe are inserted and received. The connector includes a first block configured to include a first opening into which the first fluid supply pipe is inserted, a second opening into which the external pipe and the internal pipe are inserted, and a first connection passage configured to couple the first and the second openings and form a space where the internal pipe is combined with the first fluid supply pipe and a second block formed over the first block and configured to include three or more sides directed toward different directions. Each of the three or more sides has a size in which a coupling hole into which a second fluid supply pipe is inserted and fixed is formed, one of the three or more sides forms the same plane as a side where the first opening is formed, and the other side placed on the opposite side to the one side forms the same plane as a side where the second opening is formed. The coupling hole is formed in any one of the three or more sides of the second block. A second connection passage configured to couple the coupling hole and the first connection passage of the first block is formed within the second block.

As described above, the dual pipe heat exchanger in accordance with an embodiment of the present invention includes the connector including the second block to which the second fluid supply pipe is connected. Accordingly, a dual pipe heat exchanger can be formed irrespective of the position of the second fluid supply pipe for supplying a second fluid that flows through a space between the internal pipe and the external pipe.

In the dual pipe heat exchanger in accordance with an embodiment of the present invention, like the external pipe, the internal pipe can include a plurality of protrusions protruded in the central direction of the internal pipe from an inner circumferential face thereof and extended in a straight-line form in the length direction of the internal pipe.

Meanwhile, the coupling hole may be formed to have a specific tilt angle to the first fluid supply pipe in the state in which the second fluid supply pipe is inserted into and fixed to the coupling hole, and the side of the second block where the coupling hole is formed may be formed to have a specific tilt angle to a plane parallel to the first fluid supply pipe.

As described above, since the coupling hole or the side of the second block where the coupling hole is formed has an inclined shape, the degree of freedom in the position of the second fluid supply pipe when forming a heat exchanger including a dual pipe can be increased.

Furthermore, the coupling hole may be formed so that the second fluid supply pipe is parallel to the first fluid supply pipe in the state in which the second fluid supply pipe has been inserted into and fixed to the coupling hole, and the coupling hole may be formed in any one of sides directed toward a direction different from a direction where the first and the second openings are directed, from among the sides of the second block.

Meanwhile, like the internal pipe, the first fluid supply pipe combined with the internal pipe can include a plurality of protrusions protruded in the central direction of the first fluid supply pipe from an inner circumferential face thereof and extended in a straight-line form in the length direction of the first fluid supply pipe and can be formed to have the same specification as the internal pipe. Furthermore, regarding the specification of the connector, the diameter of the first connection passage is greater than the diameter of the first opening and is smaller than the diameter of the second opening.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing an external pipe and an internal pipe which form a dual pipe heat exchanger in accordance with an embodiment of the present invention;

FIGS. 2A and 2B are perspective views of a connector which forms the dual pipe heat exchanger in accordance with an embodiment of the present invention;

FIGS. 3A and 3B show side and cross-sectional views of the connector which forms the dual pipe heat exchanger in accordance with an embodiment of the present invention;

FIG. 4 is a perspective view showing a part of the dual pipe heat exchanger in accordance with an embodiment of the present invention;

FIG. 5 is a perspective view showing a cross section of the perspective view of FIG. 4 taken along line A-A;

FIG. 6 is a cross-sectional view of a connector which forms a dual pipe heat exchanger in accordance with another embodiment of the present invention;

FIG. 7 is a cross-sectional view of a connector which forms a dual pipe heat exchanger in accordance with yet another embodiment of the present invention;

FIGS. 8A and 8B are perspective views of the connector which forms the dual pipe heat exchanger in accordance with still yet another embodiment of the present invention;

FIGS. 9A and 9B show side and cross-sectional views of a connector which forms the dual pipe heat exchanger in accordance with still yet another embodiment of the present invention;

FIG. 10 is a perspective view showing a part of the dual pipe heat exchanger in accordance with further yet another embodiment of the present invention; and

FIG. 11 is a perspective view showing a cross section of the perspective view of FIG. 10.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, some embodiments of a dual pipe heat exchanger according to the present invention are described in detail with reference to the accompanying drawings.

The present invention is not limited to the descriptions of the following embodiments, and it is evident that the present invention may be modified in various manners without departing from the technical gist of the present invention.

Meanwhile, in describing the embodiments, a description which has been widely known in the art to which the present invention pertains or has no direct relation with the technical gist of the present invention is omitted. Furthermore, in the accompanying drawings, some elements may be enlarged, omitted, or schematically shown. This is for clarifying the gist of the present invention by omitting an unnecessary description not related to the gist of the present invention.

FIG. 1 is a perspective view showing an external pipe 100 and an internal pipe 200 which form a dual pipe heat exchanger in accordance with an embodiment of the present invention.

The internal pipe 200 is a pipe through which a first fluid flows. The first fluid may become a low temperature coolant that is sucked into a compressor in an air conditioner for a vehicle or may become a high temperature coolant that is supplied to the inlet side of an expansion valve. The internal pipe 200 is combined with a first fluid supply pipe 400 having the same diameter as the internal pipe 200, such as that shown in FIG. 4. The first fluid is supplied from the first fluid supply pipe 400 to the internal pipe 200.

The internal pipe 200, as shown in FIG. 1, includes protrusions 210 protruded from the inner circumferential face of the internal pipe 200 to the central direction thereof at a specific height. The protrusions 210 are extended in a straight-line form in the length direction of the internal pipe 200 in the inner circumferential face of the internal pipe 200. The height of the protrusions 210 is not specially limited. The protrusions 210 are spaced apart from each other in the inner circumferential face of the internal pipe 200, and preferably a plurality of protrusions 210 is formed in order to improve thermal transfer efficiency. FIG. 1 illustrates that the internal pipe 200 includes the illustrated protrusions 210, but the internal pipe 200 forming a dual pipe heat exchanger according to the present invention does not need to include the protrusions 210. For example, an internal pipe without any protrusion can also be used as an element of a dual pipe heat exchanger according to the present invention.

The external pipe 100 is fabricated separately from the internal pipe 200 and is fabricated in a size that the internal pipe 200 can be inserted into the external pipe 100. The external pipe 100, as shown in FIG. 1, includes a plurality of protrusions 110 that are protruded in the central direction of the external pipe 100 in the inner circumferential face thereof at a specific height. The protrusions 110 of the external pipe 100 are formed in a straight-line form in the length direction of the external pipe 100. The height of the protrusions 110 is not specially limited. However, since the internal pipe 200 must be able to be inserted into the external pipe 100, the diameter of a virtual cylinder that couples the ends of the protrusions 110 needs to be equal to or greater than the outer diameter of the internal pipe 200.

The external pipe 100 and the internal pipe 200 are separately fabricated and the internal pipe 200 is then inserted into the external pipe 100. In order for the internal pipe 200 to maintain a stable position in the state in which the internal pipe 200 is inserted into the external pipe 100, the ends of the protrusions 110 of the external pipe 100 need to be formed at a height at which the ends can come in contact with the outer circumferential face of the internal pipe 200 or need to be formed at a height at which the ends can approach the outer circumferential face of the internal pipe 200 at a minimum interval.

When the internal pipe 200 is inserted into the external pipe 100, a plurality of passages partitioned by the plurality of protrusions 110 of the external pipe 100 is formed between the internal pipe 200 and the external pipe 100. The plurality of passages becomes a plurality of passages for a second fluid that is different from the first fluid. The second fluid has different properties from the first fluid. The second fluid may become a low temperature coolant that is sucked into a compressor in an air conditioner for a vehicle or may become a high temperature coolant that is supplied to the inlet side of an expansion valve. If the first fluid supplied to the internal pipe 200 is a low temperature coolant, the second fluid becomes a high temperature coolant. If the first fluid is a high temperature coolant, the second fluid becomes a low temperature coolant. The first and the second fluids have only to have different physical properties so that heat can be transferred, but do not need to be coolants having specific temperature and pressure conditions.

FIGS. 2A and 2B are perspective views of a connector 300 that forms a dual pipe heat exchanger in accordance with an embodiment of the present invention.

The connector 300 is configured to basically include a first block 310 and a second block 320. The first block 310 has a cylindrical shape having a through hole formed at a central portion thereof, and the second block 320 has a cylindrical shape having an opening formed on one side thereof. The first block 310 has a greater diameter than the second block 320, and the second block 320 is formed over the first block 310. The first block 310 and the second block 320 are not limited to the shapes illustrated in FIGS. 2A and 2B and may be fabricated to have shapes different from the illustrated shapes. The second block 320 preferably is formed to have a polyhedron shape having three or more sides. The three or more sides of the second block 320, that is, the polyhedron, are formed in different directions. For example, in FIGS. 2A and 2B according to embodiments of the present invention, the second block 320 of the connector 300 is illustrated as including a pair of sides opposite to each other, thus having a total of four sides.

As shown in FIG. 1, the first block 310 includes a dual pipe in which the internal pipe 200 is inserted into the external pipe 100 and a space into which the first fluid supply pipe 400 (seen FIG. 4) combined with the internal pipe 200 is inserted, and the second block 320 includes a space into which a second fluid supply pipe 500 (see FIG. 5) is inserted and fixed. Meanwhile, the first block 310 and the second block 320 are integrally formed.

A second opening 312 into which a dual pipe configured to have the internal pipe 200, such as that shown in FIG. 1, inserted into the external pipe 100 is inserted and a first opening 311 into which the first fluid supply pipe 400 combined with the internal pipe 200 and configured to supply the first fluid is inserted are formed in the first block 310 of the connector 300. The first opening 311 and the second opening 312 are coupled by a first connection passage 313, and thus a through passage is formed from the first opening 311 to the second opening 312.

A coupling hole 321 into which the second fluid supply pipe 500 can be inserted into is formed on one side 323 of the second block 320 of the connector 300. FIG. 2A is a perspective view of the connector 300 in a direction from which the side 323 of the second block 320 having the coupling hole 321 formed therein is seen. In the connector 300 shown in FIG. 2A, the first opening 311 into which the first fluid supply pipe 400 is inserted and fixed and the coupling hole 321 into which the second fluid supply pipe 500 is inserted are formed in the respective sides of the first block 310 and the second block 320 which are directed in the same direction, but the connector 300 according to the present invention is not necessarily limited thereto. The coupling hole 321 into which the second fluid supply pipe 500 is inserted and fixed may be formed on the side opposite to the side 323 shown in FIG. 2A (i.e., the side of the second block 320 shown in FIG. 2B).

FIG. 2B is a perspective view of the connector 300 in a direction from which the second opening 312 into which the internal pipe 200 and the external pipe 100 are inserted is seen. As shown in FIG. 2B, a second connection passage 322 is formed at the boundary portion of the second block 320 and the first block 310 and configured to couple the coupling hole 321 of the second block 320 and the first connection passage 313 of the first block 310.

FIGS. 3A and 3B show side and cross-section views of the connector 300 shown in FIGS. 2A and 2B. FIG. 3A is a diagram in which a side in which the first opening 311 of the first block 310 and the coupling hole 321 of the second block 320 are formed is seen from the front.

In the connector 300 of FIG. 3A, the first block 310 has a cylindrical shape having a circular section, and the second block 320 is formed over the first block 310 at a specific height. The section of an upper portion of the second block 320 has a semi-circle shape. As shown in FIG. 3A, the first block 310 is configured to penetrate from the first opening 311 to the second opening 312 via the first connection passage 313.

As shown in FIG. 3B, the first connection passage 313 of the first block 310 is connected to the coupling hole 321 of the second block 320 by the second connection passage 322 of the second block 320. Accordingly, the second fluid supplied through the second fluid supply pipe 500 that is inserted into and fixed to the coupling hole 321 flows into an upper portion of the first connection passage 313 via the second connection passage 322 and then flows into the space between the internal pipe 200 and the external pipe 100 that are inserted into the first connection passage 313.

Meanwhile, the diameter D1 of the first opening 311 of the first block 310 is smaller than the diameter D3 of the first connection passage 313, and the diameter D2 of the second opening 312 is greater than the diameter D3 of the first connection passage 313. Since the diameter D3 of the first connection passage 313 is smaller than the diameter D2 of the second opening 312, the external pipe 100 of the pipes inserted into the second opening 312 has an end come in contact with a step portion formed at the boundary of the second opening 312 and the first connection passage 313, so that the position of the external pipe 100 is fixed. The internal pipe 200 is inserted up to the first connection passage 313 via the second opening 312 and is combined with the first fluid supply pipe 400 that is inserted up to the first connection passage 313 via the first opening 311. In other words, the first fluid supply pipe 400 and the internal pipe 200 are combined in the first connection passage 313, and the second fluid flows into the spaces outside the first fluid supply pipe 400 and the internal pipe 200.

FIGS. 4 and 5 are perspective views showing that the internal pipe 200, the external pipe 100, and the first and the second fluid supply pipes 400 and 500 are combined with the connector 300 in a dual pipe heat exchanger in accordance with an embodiment of the present invention.

As shown in FIGS. 4 and 5, the first fluid supply pipe 400 inserted via the first opening 311 and the internal and external pipes 200 and 100 inserted via the second opening 312 are combined with sides opposite to each other, of the first block 310 of the connector 300. The second fluid supply pipe 500 is inserted into and fixed to one side 323 of the second block 320 where the coupling hole 321 is formed.

A pipe having the same diameter as the internal pipe 200 can be used as the first fluid supply pipe 400 inserted into the first opening 311. In the case of the first fluid supply pipe 400 shown in FIGS. 4 and 5, the protrusions 410 are formed in the inner circumferential face of the first fluid supply pipe 400 as in the internal pipe 200, but the present invention is not limited thereto. For example, a pipe without any protrusion may be used.

The first and the second fluid supply pipes 400 and 500 can be combined with the connector 300 in various manners, and a method of coupling the first and the second fluid supply pipes 400 and 500 and the connector 300 is not limited to a specific method. For example, the first and the second fluid supply pipes 400 and 500 and the connector 300 may be adhered together using a method, such as welding, or other mechanical methods. The external pipe 100 inserted into and fixed to the second opening 312 may be combined with the connector 300 using a method, such as welding, or other mechanical methods. A method of combining the external pipe 100 and the connector 300 is not limited to a specific method.

As shown in FIG. 5, the first fluid supply pipe 400 is inserted up to the first connection passage 313, and thus one end of the first fluid supply pipe 400 is combined with one end of the internal pipe 200. The protrusions 410 of the first fluid supply pipe 400 and the protrusions 210 of the internal pipe 200 may be formed at respective positions corresponding to each other as shown in FIG. 5, thus being capable of having a general straight-line form, but are not necessarily limited thereto.

FIG. 6 shows a cross section of a connector 300′ of a dual pipe heat exchanger in accordance with a modified example of the present invention. The connector 300′ of FIG. 6 has the same section shape as the connector 300 of FIG. 3B except the shape of the coupling hole 321 of the second block 320.

The coupling hole 321 of the connector 300 shown in FIGS. 3A and 3B is formed in a direction vertical to the side 323 of the second block 320, whereas the coupling hole 321′ formed in the second block 320 of the connector 300′ shown in FIG. 6 is inclined against the side 323 of the second block 320 at a specific angle. That is, when the first fluid supply pipe 400 and the second fluid supply pipe 500 are inserted into and fixed to the connector 300 shown in FIGS. 3A and 3B, the first and the second fluid supply pipes 400 and 500 are parallel to each other. In contrast, when the first and the second fluid supply pipes 400 and 500 are inserted into and fixed to the connector 300′ shown in FIG. 6, the second fluid supply pipe 500 has a specific tilt angle to the first fluid supply pipe 400.

If the coupling hole 321′ into which the second fluid supply pipe 500 is inserted has a specific tilt angle to a direction where the first opening 311 is formed as described above, when the second fluid supply pipe 500 is inserted into and fixed to the second block 320 of the connector 300, the second fluid supply pipe 500 is obliquely fixed at a specific tilt angle to the first fluid supply pipe 400. As shown in FIG. 6, the tilt angle of the coupling hole 321 may have a specific value within a range from greater than 0° to less than 90°. The tilt angle of the coupling hole 321′ can be properly selected depending on the characteristics of a place where a dual pipe heat exchanger will be installed or the positions of other elements of an air conditioner including a dual pipe heat exchanger. Accordingly, in the case of a dual pipe heat exchanger according to the present invention, a wide degree of freedom in the design can be secured.

A connector 300″ in accordance with another modified example of the present invention shown in FIG. 7 has the same cross-sectional shape as the connector 300 of FIG. 3B except that a side 323″ where a coupling hole 321 is formed is tilted at a specific tilt angle.

The side 323 where the coupling hole 321 or 321′ is formed, from among the sides of the second block 320 shown in FIG. 3B or FIG. 6, is configured to have the same plane as the side where the first opening 311 of the first block 310. In contrast, the side 323″ where the coupling hole 321 is formed in FIG. 7 is inclined at a specific tilt angle to a plane parallel to the first fluid supply pipe 400 in the state in which the first fluid supply pipe 400 has been inserted into the first opening 311.

Like the tilt angle of the coupling hole 321′ shown in FIG. 6, the tilt angle of the side 323″ of the second block 320 of FIG. 7 may have a specific value within a range from greater than 0° to less than 90°. The tilt angle of the side 323″ can be properly selected depending on the characteristics of a place where a dual pipe heat exchanger will be installed or the positions of other elements of an air conditioner including a dual pipe heat exchanger.

FIGS. 8A and 8B are perspective views of a connector 300 which forms a dual pipe heat exchanger in accordance with yet another embodiment of the present invention.

The connector 300 of FIGS. 8A and 8B has the same shape as the connector 300 of FIGS. 2A and 2B except the positions of a coupling hole 321 into which the second fluid supply pipe 500 is inserted and fixed.

In the connector 300 of FIGS. 8A and 8B, the coupling hole 321 is formed in another side 324 neighboring the side 323 of the second block 320 of the connector 300 shown in FIGS. 2A and 2B. In FIGS. 8A and 8B, an upper end part of the side 324 of the second block 320 has a curved part not a flat plane, but the connector in accordance with a modified example of the present invention is not necessarily limited thereto.

FIGS. 9A and 9B show side and cross-sectional views of the connector shown in FIGS. 8A and 8B.

In the connector 300 of FIGS. 9A and 9B, unlike in the connector 300 of FIG. 3A, no opening is formed in the side 323 that is directed toward the same direction as a side where a first opening 311 is formed, from among the sides of the second block 320, and a second opening 321 (i.e., the coupling hole) is formed in the side 324 neighboring the side 323. The two neighboring sides 323 and 324 of the second block 320 of the connector 300 shown in FIGS. 9A and 9B are configured to be vertical to each other, but the present invention is not limited thereto. For example, an angle formed by the two neighboring sides 323 and 324 of the second block 320 may be greater than or smaller than 90°.

FIGS. 10 and 11 are perspective views showing a state in which first and second fluid supply pipes 400 and 500 and internal and external pipes 200 and 100 are inserted into and fixed to the connector 300 shown in FIGS. 8A and 8B. As shown in FIGS. 10 and 11, the coupling hole 321 formed in the second block 320 is formed in the side 324 neighboring the side in which the first opening 311 is formed. Thus, the first fluid supply pipe 400 and the second fluid supply pipe 500 are fixed at a right angle. An angle formed by the first fluid supply pipe 400 and the second fluid supply pipe 500 is not necessarily limited to 90°. For example, the angle formed by the first fluid supply pipe 400 and the second fluid supply pipe 500 may be greater than or smaller than 90° depending on an angle formed by the side 324 where the coupling hole 321 is formed and the side where the first opening 311 is formed.

As shown in FIGS. 6 to 11, in the connector 300, 300′, 300″ forming the dual pipe heat exchanger according to the present invention, the position of the coupling hole 321 into which the second fluid supply pipe 500 is inserted and fixed can be changed in various manners. Accordingly, the connector of FIGS. 6 to 11 functions as a multi-directional connector in that a dual pipe heat exchanger can be installed in a form suitable for each case irrespective of the characteristics of a place where the dual pipe heat exchanger will be installed or a relationship between the positions of other elements of an air conditioner including the dual pipe heat exchanger. For example, assuming that an element for supplying the first fluid is placed on the left side of the dual pipe heat exchanger in FIG. 4, if an element for supplying the second fluid is placed on the left side of the dual pipe heat exchanger, a connector in which the coupling hole 321 is formed has only to be used in the same side 323 as the side where the first opening 311 is formed as shown in FIG. 4. If an element for supplying the second fluid is placed on the front side in the length direction of the dual pipe heat exchanger, the connector where the coupling hole 321 is formed has only to be used in the side 324 that neighbors the side where the first opening 311 is formed as shown in FIG. 10.

In the case of the connector included in the dual pipe heat exchanger according to the present invention as described above, the second block 320 is formed over the first block 310 into which the first fluid supply pipe 400 and the internal and external pipes 200 and 100 are inserted and combined, and the second fluid supply pipe 500 is combined with the second block 320. Accordingly, there are advantages in that the connector of the present invention can function as a multi-directional connector and the coupling hole 321 can be formed at a proper position according to the characteristics of an air conditioner where the dual pipe heat exchanger will be installed.

Meanwhile, each of the aforementioned dual pipe heat exchangers in accordance with the embodiments of the present invention may be used as one of the elements of an air conditioner for a vehicle or may be used in other air conditioners.

The dual pipe heat exchanger according to the present invention is advantageous in that it can be installed in a minimum space more easily because the first fluid supply pipe for supplying a fluid between the external pipe and the internal pipe can be combined with the external pipe in various directions and at various angles and a variety of design changes are possible in installing the dual pipe heat exchanger.

Furthermore, the dual pipe heat exchanger according to the present invention is advantageous in that it can improve heat exchange efficiency between a fluid flowing through the internal pipe and a fluid flowing between the external pipe and the internal pipe because the protrusions extending in the length direction are provided in each of the external pipe and the internal pipe and thus overall heat exchange efficiency can be improved.

The detailed contents described above are only an embodiment of the dual pipe heat exchanger according to the present invention. The contents present only a specific example in order to help understanding of the technical gist and major elements of the present invention and are not intended to limit the scope of the present invention. Those skilled in the art will appreciate that various modifications, additions and substitutions are possible without departing from the scope and spirit of the invention as disclosed in the accompanying claims. 

What is claimed is:
 1. A dual pipe heat exchanger, comprising: an external pipe configured to have a plurality of protrusions formed therein, the protrusions being protruded in a central direction of the external pipe from an inner circumferential face thereof and extended in a straight-line form in a length direction of the external pipe; an internal pipe inserted into the external pipe; a first fluid supply pipe combined with one end of the internal pipe; and a connector configured to comprise a space in which the external pipe, the internal pipe, and the first fluid supply pipe are inserted and received, wherein the connector comprises a first block configured to comprise a first opening into which the first fluid supply pipe is inserted, a second opening into which the external pipe and the internal pipe are inserted, and a first connection passage configured to couple the first and the second openings and form a space where the internal pipe is combined with the first fluid supply pipe and a second block formed over the first block and configured to comprise three or more sides directed toward different directions; each of the three or more sides has a size in which a coupling hole into which a second fluid supply pipe is inserted and fixed is formed, one of the three or more sides forms an identical plane with a side where the first opening is formed, and the other side placed on an opposite side to the one side forms an identical plane with a side where the second opening is formed; the coupling hole is formed in any one of the three or more sides of the second block; and a second connection passage configured to couple the coupling hole and the first connection passage of the first block is formed within the second block.
 2. The dual pipe heat exchanger of claim 1, wherein the internal pipe comprises a plurality of protrusions protruded in a central direction of the internal pipe from an inner circumferential face thereof and extended in a straight-line form in a length direction of the internal pipe.
 3. The dual pipe heat exchanger of claim 1, wherein the coupling hole is formed to have a specific tilt angle to the first fluid supply pipe in a state in which the second fluid supply pipe is inserted into and fixed to the coupling hole.
 4. The dual pipe heat exchanger of claim 1, wherein the side of the second block where the coupling hole is formed is formed to have a specific tilt angle to a plane parallel to the first fluid supply pipe.
 5. The dual pipe heat exchanger of claim 1, wherein the coupling hole is formed so that the second fluid supply pipe is parallel to the first fluid supply pipe in a state in which the second fluid supply pipe has been inserted into and fixed to the coupling hole.
 6. The dual pipe heat exchanger of claim 1, wherein the coupling hole is formed in any one of sides directed toward a direction different from a direction where the first and the second openings are directed, from among the sides of the second block.
 7. The dual pipe heat exchanger of claim 1, wherein a diameter of the first connection passage is greater than a diameter of the first opening and is smaller than a diameter of the second opening.
 8. An air conditioner for a vehicle comprising the dual pipe heat exchanger according to claim
 1. 